<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<meta http-equiv="X-UA-Compatible" content="IE=edge">
	<title></title>
	<link rel="stylesheet" href="">
</head>
<body>
	<script>
		var name = 'World!';
		(function () {
		    if (typeof name === 'undefined') {
		        var name = 'Jack';
		        console.log('Goodbye ' + name);
		    } else {
		        console.log('Hello ' + name);
		    }
		})();
		// goodby Jack
	</script>
</body>
</html>